Puck a, of inertia m, is attached to one end of a string of length ℓ , and the other end of the string is attached to a pivot so that the puck is free to revolve on a smooth horizontal surface. puck b, of inertia 16m, is attached to one end of a string of length ℓ/2, and the other end of the string is attached to a second pivot so that b is also free to revolve. in each case, the puck is held as far as possible from the pivot so that the string is taut and then given an initial velocity v⃗ perpendicular to the string. a. how does the magnitude of the angular momentum of puck a about its pivot compare with that of puck b about its pivot?
b. how does the rotational kinetic energy of a compare with that of b?

As part of an industrial process, air as an ideal gas at 10 bar, 400k expands at steady state through a valve to a pressure of 4 bar. the mass flow rate of air is 0.5 kg/s. the air then passes through a heat exchanger where it is cooled to a temperature of 295k with negligible change in pressure. the valve can be modeled as a throttling process, and kinetic and potential energy effects can be neglected. (a) for a control volume enclosing the valve and heat exchanger and enough of the local surroundings that the heat transfer occurs at the ambient temperature of 295 k, determine the rate of entropy production, in kw/k. (b) if the expansion valve were replaced by an adiabatic turbine operating isentropically, what would be the entropy production? compare the results of parts (a) and (b) and discuss.

High schoolphysics 5+3 pts a neon light consists of a glass tube with metal wires at each end. when connected to a high-voltage source, the gas glows. if a fly lands on the glass tube, what will most likely happen? a) the fly will not feel a shock because the glass conducts any free electrons back into the gas. b) electrons will flow directly from the metal wires along the glass and shock the fly. c) the fly will not feel a shock because the glass insulates it from the electrons in the gas and the metal. d) electrons that are moving through the gas will be conducted through the glass and shock the fly.

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j? 1. write the equation 2.list out your known variables 3.plug the numbers into the equations 4.solve 5.write your solution statement that includes initial energy and final